An inherent advantage in using optical methods in information processing is that these systems can perform data processing operations in parallel. In contrast to the advantage provided by parallel processing, the space invariance of most conventional imaging techniques limits the utilization of optical data processing techniques in certain instances. For example, the features of both parallel processing and space variance are necessary for general map transformations using optical schemes.
Although prior art elements such as corrector plates, axicons, conical lenses and ring lenses have been utilized to provide local image modifications, they are generally inadequate for purposes of information processing.
Alternate techniques for providing general types of coordinate transformations as well as local image modifications include image processing with digital techniques, fiber optic devices and scanning systems, both optical and electronic. These techniques, however, are indirect and relatively complex.
Therefore a need exists for a direct, relatively noncomplex optical technique for providing a space variant system which, in turn, allows general types of coordinate transformation as well as local image modifications such as translation, stretching and rotation to be achieved.